Reported Lyme disease cases in Wisconsin on the rise

This summer’s warm, wet weather, a migration of bugs from up north and generally better reporting methods have led to a surge in Lyme disease across central Wisconsin.

Health departments are reporting spikes in Lyme disease throughout the state, including in Marathon County where 174 cases of the tick-borne illness were reported this year as of Tuesday, easily exceeding 2009’s 122 total cases, county data shows.

Fifty-three cases have been confirmed in Lincoln County this year, compared to a total of 69 in 2009.

Diep Hoang Johnson, an epidemiologist for Wisconsin’s Division of Public Health, said more infected ticks are making their way east as deer, birds and small mammals carry them throughout the state.

In a 2008 study, eight counties in eastern Wisconsin had deer ticks — the tick species that carries Lyme disease — that a decade ago were free from the parasite, Johnson said. Marathon and Lincoln counties had Lyme disease at the time, but reported cases were significantly lower than today.

Lyme disease, which can lead to serious conditions such as arthritis, meningitis and heart conditions if untreated, is spread to humans through deer tick bites.

The state has seen a steady uptick in Lyme disease since 2000, when 658 cases were confirmed. In 2009, the state division of public health confirmed 1,948 cases and identified 636 as probable.